1//===- ELFDynObjReader.cpp ------------------------------------------------===//
2//
3//                     The MCLinker Project
4//
5// This file is distributed under the University of Illinois Open Source
6// License. See LICENSE.TXT for details.
7//
8//===----------------------------------------------------------------------===//
9#include <mcld/LD/ELFDynObjReader.h>
10
11#include <mcld/LinkerConfig.h>
12#include <mcld/IRBuilder.h>
13#include <mcld/LD/ELFReader.h>
14#include <mcld/MC/Input.h>
15#include <mcld/Target/GNULDBackend.h>
16#include <mcld/Support/MemoryArea.h>
17
18#include <llvm/ADT/StringRef.h>
19#include <llvm/ADT/Twine.h>
20#include <llvm/Support/ErrorHandling.h>
21
22#include <string>
23
24using namespace mcld;
25
26//===----------------------------------------------------------------------===//
27// ELFDynObjReader
28//===----------------------------------------------------------------------===//
29ELFDynObjReader::ELFDynObjReader(GNULDBackend& pBackend,
30                                 IRBuilder& pBuilder,
31                                 const LinkerConfig& pConfig)
32  : DynObjReader(),
33    m_pELFReader(0),
34    m_Builder(pBuilder) {
35  if (pConfig.targets().is32Bits() && pConfig.targets().isLittleEndian())
36    m_pELFReader = new ELFReader<32, true>(pBackend);
37  else if (pConfig.targets().is64Bits() && pConfig.targets().isLittleEndian())
38    m_pELFReader = new ELFReader<64, true>(pBackend);
39}
40
41ELFDynObjReader::~ELFDynObjReader()
42{
43  delete m_pELFReader;
44}
45
46/// isMyFormat
47bool ELFDynObjReader::isMyFormat(Input &pInput, bool &pContinue) const
48{
49  assert(pInput.hasMemArea());
50
51  // Don't warning about the frequently requests.
52  // MemoryArea has a list of cache to handle this.
53  size_t hdr_size = m_pELFReader->getELFHeaderSize();
54  if (pInput.memArea()->size() < hdr_size)
55    return false;
56
57  llvm::StringRef region = pInput.memArea()->request(pInput.fileOffset(),
58                                                     hdr_size);
59
60  const char* ELF_hdr = region.begin();
61  bool result = true;
62  if (!m_pELFReader->isELF(ELF_hdr)) {
63    pContinue = true;
64    result = false;
65  } else if (Input::DynObj != m_pELFReader->fileType(ELF_hdr)) {
66    pContinue = true;
67    result = false;
68  } else if (!m_pELFReader->isMyEndian(ELF_hdr)) {
69    pContinue = false;
70    result = false;
71  } else if (!m_pELFReader->isMyMachine(ELF_hdr)) {
72    pContinue = false;
73    result = false;
74  }
75  return result;
76}
77
78/// readHeader
79bool ELFDynObjReader::readHeader(Input& pInput)
80{
81  assert(pInput.hasMemArea());
82
83  size_t hdr_size = m_pELFReader->getELFHeaderSize();
84  llvm::StringRef region = pInput.memArea()->request(pInput.fileOffset(),
85                                                     hdr_size);
86  const char* ELF_hdr = region.begin();
87
88  bool shdr_result = m_pELFReader->readSectionHeaders(pInput, ELF_hdr);
89
90  // read .dynamic to get the correct SONAME
91  bool dyn_result = m_pELFReader->readDynamic(pInput);
92
93  return (shdr_result && dyn_result);
94}
95
96/// readSymbols
97bool ELFDynObjReader::readSymbols(Input& pInput)
98{
99  assert(pInput.hasMemArea());
100
101  LDSection* symtab_shdr = pInput.context()->getSection(".dynsym");
102  if (NULL == symtab_shdr) {
103    note(diag::note_has_no_symtab) << pInput.name()
104                                   << pInput.path()
105                                   << ".dynsym";
106    return true;
107  }
108
109  LDSection* strtab_shdr = symtab_shdr->getLink();
110  if (NULL == strtab_shdr) {
111    fatal(diag::fatal_cannot_read_strtab) << pInput.name()
112                                          << pInput.path()
113                                          << ".dynsym";
114    return false;
115  }
116
117  llvm::StringRef symtab_region = pInput.memArea()->request(
118      pInput.fileOffset() + symtab_shdr->offset(), symtab_shdr->size());
119
120  llvm::StringRef strtab_region = pInput.memArea()->request(
121      pInput.fileOffset() + strtab_shdr->offset(), strtab_shdr->size());
122  const char* strtab = strtab_region.begin();
123  bool result = m_pELFReader->readSymbols(pInput, m_Builder,
124                                          symtab_region, strtab);
125  return result;
126}
127
128